Aerial system employed in wireless telegraphy and telephony



c. s. FRANKLIN. AERIAL SYSTEM EMPLOYED IN WIRELESS TELEGRAPHY AND TELEPHONY.

APPLICATION FILED AUG.26, 1920.

Patented Feb. 15, 1921.

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AERTAL SYSTEM. EBZ'CPLOYED IN,WIRELESS TELEGBAPHY AND TELEPHQNT'.

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' Specification of Letters Patent.

Patented Feb. 15, 1921.

Application filed August 26, 1920. Serial Ito. 406,173.

To all whom it may concern:

Be it known that I, CHARLES SAMUEL FRANKLIN, a'subject of the King of Great Britain, and resident of St. Michaels, Westbury Lane, Buckhurst Hill, in the county of Essex, England, have invented new and useful Tm rovements in Aerial Systems Employed in Wireless Telegraphy, and Telephony, of which the following isv a specification.

When a system of spaced serials is employed for directional working in wireless telegraph it is very desirable that the tuning of al the aerials should be under control at one central place.

This has been done by bringing a pair of parallel wires connected to each aerial to the'central place and locating the necessary tuning inductances and condensers there.

When however the wires are a considerable fraction of a wave length'it is found that although the aerial can be tuned by adjusting the condenser or inductance, there is a strong tendency for the aerial and wires to oscillate as a long horizontal aerial and so directional properties of the aerial are im aired.

ccording to this invention, instead of connecting the horizontal parallel wires directly to the aerial, I connect the aerial to one windin of a transformer, and I connect the wires to the other winding.

Preferably an earthed shieldis interposed between the windings of the traglsiormer.

A similar transformer may e connected to the other end of the wires, one winding being connected to the wires andthe other winding to the tuning elements. Such transformers may also be interposedat intermediate places along the connecting wires.

The invention is illustrated in the drawing. A is a frame aerial, B the connecting wires, .1 and C the tuning inductance and condenser near to the receiver R.- 1, 2,3 are transformers having an earthed shield interposing between the two windings of each.

I have found that such an arrangement enables aerial A to be tuned by means of the tuning elements l and 0 located a considerable fraction of a wave length from A, and at the same time the aerial A and wires B are prevented from oscillating as a long horizontal aerial.

.. tuning The transformers 1, 2 and 3 are preferably wound to havevery small leakage and small capacity between the windings and between the windings and theearth screen. The nductance oi each transformer windmg should be high compared 'with the inductance of the aerial A.

The lnvention is illustrated as applied to a frame aerial, but it can be applied to any type of aerial.

What I claim is 1. At a wireless station, the combination of an aer1al, a primary winding therein, a secondary winding closely coupled to the primary winding whereby the leakage coefiiclent 1s minimized, a line circuit connected to the secondary winding and means connected in the line circuit for tuning the aerial system.

2. At a wireless station the combination of an aerial, a primary Winding therein, a secondary winding closely coupled to the primary winding whereby the leakage coeificient 1s m1nimized,a line circuit connected to the secondary winding and means for the aerial system connected in the l ne circuit and spaced a considerable fract1on of wave length "from the aerial.

3. At a wireless station, the combination of an aer1al, a primary winding therein, a secondary windmg, an earthed shield between the windings, lines connected to this secondary winding and means connected to the lines for tuning the aerial system.

4. At a wireless station, the combination of an aer1al, a primary winding therein, a secondary w nding, an earthed shield between the wmdings, lines connected to the secondary winding and means for tuning the aerial system connected to the lines and spaced a considerable fraction of a wave length from the aerial.

5. At'a wireless station the combination of an aerial, a primary winding therein, a

secondary winding closely coupled to' the prlmary'windin whereby the leakage coeiliclent is minim1zed, a line circuit connected to the secondary winding, a receivin circuit coupled to the line circuit and space a considerable traction of a wave length from the aerial and means for tunin the aerial system connected in the line circuit in proximity to the receiving circuit.

6. At a wireless station, the combination of an aerial, tuning means situated at a distance therefrom, lines extending between the aerial and tuning means, a transformer between the aerial and lines and an additional transformer having its primary and secondary in the lines interposed between the aerial and tuning means.

7. At a wireless station, the combination of n aerial, tuning means situated at a distance therefrom, lines extendingbetween the aerial and the tuning means and a plurality of transformers having their primaries and secondaries in the lines interposed between the aerial and the tuning means.

8. At a wireless station, the combination of an aerial, tuning means situated at a distance therefrom, lines extending between the aerial and the tuning means, a plurality of transformers interposed between the aerial and the tuning means, and an earthed shield naeaaaa between the two windings of each transformer. v

9. At a wireless station, the combination of an aerial, a primary winding therein, a secondary winding of high inductance as compared with the inductance of said aerial, said secondary'winding being closely coupled to the rimary windingi 'yvhereby the leakage coefii cient is minimized, a line circuit connected to the secondary winding and means connected in the line circuit for tuning the aerial system.

In testimony that I claim the foregoing as my invention I have signed my name this thirtieth day of July, 1920.

CHARLES SAMUEL FRANKLIN. 

